Scooters are a popular form of personal transport. Some scooters have a collapsible structure allowing them to be folded into a compact state.
U.S. Pat. No. 6,616,154 to Neuhold describes a foldable kick scooter comprising a footboard which forms bearing forks for wheels and on which is held a guide bearing for the bearing forks of the front wheel, which is connected to a steering column which is divided into linked elements and can be swiveled about a transversal axle against the footboard. In order to provide advantageous construction conditions it is proposed that both the guide bearing for the front bearing fork as well as the rear bearing fork are held downwardly swivelable about parallel transversal axles towards the footboard and that the footboard forms two through-openings for the swiveled wheels.
U.S. Pat. No. 5,183,129 to Powell describes a collapsible scooter, described as improved and highly portable, having a front frame extending upwardly from a front portion of a lower frame and being pivotally secured thereto. The front frame is secured at its upper end to steering means, and a front wheel is rotatably secured to the steering means. A rear wheel is rotatably secured to a rear portion of the lower frame, and a platform for supporting a rider is secured to the lower frame between the front and rear wheels. Lock means releasably lock the front frame and lower frame in an operating position or in a collapsed position in which the front frame extends rearwardly from the front portion of the lower frame. An engine is preferably coupled with the rear wheel of the scooter using a belt drive system which preferably includes toothed pulleys and a notched drive belt.
PCT Publication WO 2007-128124 to Atherton et al. describes a scooter having a platform on which a rider can stand, a front wheel attached to a steering system including an upstanding handle bar and rear wheel which is driven. The scooter can be folded at a hinge line across the platform so as to allow it to collapse. A case for the scooter includes a front part and a rear part covering the front and rear wheels with the parts brought together by the collapsing of the platform. This folding action also uses a pivot link to move the front and rear wheels pivoted within the respective case parts to a folded position. The steering includes a headstock with the steering bar connected to the front fork by a drive coupling which converts the rotation of the steering bar about the generally vertical axis to the rotation of the fork about an inclined axis.
The following patents and patent applications may be of interest:    CN 2706392Y    DE 10038261    DE 10045821    DE 29723276    DE 298151620    DE 9213474U    EP 0362033    FR 2478569    FR 2915454    GB 2279921    WO 2001-05646    WO 2002-12057    WO 2003-093093    WO 2008-090309    US 2002-0088834    US 2002-0093161    US 2002-0104863    US 2003-0001351    US 2003-0085539